As the demand for high speed broadband networking over wireless communication links increases, so too does the demand for different types of networks that can accommodate high speed wireless networking. For instance, the deployment of Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 wireless networks in homes and business to create Internet access “hot spots” has become prevalent in today's society. However, these IEEE 802.11-based networks are limited in bandwidth as well as distance. For example, maximum typical throughput from a user device to a wireless access point is 54 MB/sec. at a range of only a hundred meters or so. In contrast, while wireless range can be extended through other technologies such as cellular technology, data throughput using current cellular technologies is limited to a few MB/sec. Put simply, as the distance from the base station increases, the need for higher transmission power increases and the maximum data rate typically decreases. Accordingly, there is a need to support high-speed wireless connectivity beyond a short distance such as within a home or office.
As a result of the demand for longer range wireless networking, the IEEE 802.16 standard was developed. The IEEE 802.16 standards are often referred to as WiMAX or less commonly as WirelessMAN or the Air Interface Standard. These standards provide specifications for fixed broadband wireless metropolitan access networks (“MAN”s) that use a point-to-multipoint architecture (IEEE 802.16d) and combined fixed and mobile broadband wireless access system's (IEEE 802.16e). The WiMAX Forum and its Network Working Group (“NWG”) are defining the IEEE 802.16 network architecture and recently issued the NWG Stage-3 draft. Such communications can be implemented, for example, using orthogonal frequency division multiplexing (“OFDM”) and orthogonal frequency division multiplexing access (“OFDMA”). OFDM is a multi-carrier transmission technique that has been recognized as an excellent method for high-speed bi-directional wireless data communications. Fundamentally, frequency division multiplexing (“FDM”) uses multiple frequencies to simultaneously transmit multiple signals in parallel. While each sub-carrier is separated by a guard band to ensure that they do not overlap in the ordinary FDM, the sub-carriers in the OFDM are squeezed tightly together in order to reduce the required bandwidth. In fact the neighboring sub-channels are overlapped in OFDM. However, the sub-carriers are orthogonal to each other such that there is no inter-carrier interference (“ICI”).
The 802.16 standards support high bit rates in both uploading and downloading from a base station up to a distance of about 30 miles (about 50 km) to handle real-time services and bandwidth-intensive applications such as streaming music and video, video surveillance, voice over IP (“VoIP”), video conferencing and other voice and data formats, e.g., time division multiplexing (“TDM”). A typical WiMAX network provides up to 75 megabit per second (“mbps”) bandwidth and up to a 50 km range. The 802.16 standard defines a media access control (“MAC”) layer that supports multiple physical layer specifications customized for the frequency band of use and their associated regulations. This MAC layer uses protocols to ensure that signals sent from different stations using the same channel do not interfere with each other and “collide”.
The 802.16 standards are connection-oriented protocols. Even the management message is based on the preset connection ID (“CID”), which is defined by 802.16 standards as a 16-bit value that identifies a connection to equivalent peers in the MAC of a base station (“BS”) and a mobile subscriber station (“MS”). Each connection is assigned a unique CID that maps to a service flow identifier (“SFID”), which is defined by 802.16 standards as a 32-bit value that uniquely identifies a service flow to both a MS and a BS. A SFID defines the quality of service (“QoS”) parameter set for a service flow associated with a connection. As such, service flow plays a central role in the technology. Each service flow is associated with zero or one connection depending on the operational mode, e.g., unicast, multicast and broadcast.
Currently, there is a lack of SFID mobility when a mobile subscriber station (“MS”) attempts to effect a handover from a serving BS to a target BS, especially during handover between a serving BS communicating with one access service network (“ASN”) gateway (“GW”) and a target BS communicating with another ASN GW. Each time there is a handover of a MS, the SFID is recalculated and updated to create a new SFID with respect to the new connection that is established. Several attempts to solve this problem have been proposed.
One attempt uses an access service network gateway to assign an ASN GW-wide unique SFID. However, there is no global mobility for this ASN GW-wide unique SFID, nor any multicast service. Another attempt uses a BS assign a BS-wide unique SFID. However, here again, there is no global mobility for this BS-wide unique SFID, and no multicast service within a corresponding ASN GW.
It is therefore desirable to have methods and systems to provide global mobility of a SFID across multiple BSs and ASN GWs that can include additional service flow parameters such as multicast service support and backhaul data path (service flow) granularity.